Not Applicable
Not Applicable
1. Field of Invention
This invention relates to the field of personal hydration systems used by runners or joggers.
2. Discussion of Prior Art
Running, cycling, and other forms of exercise produce an increased need for water intake to compensate for that lost by respiration, perspiration, and urinary output. This need, if not met, may become life threatening during prolonged high-intensity activity in hot weather. It is therefore desirable to be able to carry on one""s person an adequate supply of water or other hydrating fluid.
Although hydration systems are in common use by cyclists, prior art hydration systems for runners have not met two essential design criteria. One is that the device must utilize a stable, non-irritating waist-mounted system with sufficient motion control to minimize bounce and sway. Another is that the device must provide a simple, lightweight, and inexpensive means for delivering fluid from waist level to mouth level.
One type of hydration system for runners utilizes one or more water bottles attached to a waist-mounted belt. U.S. Pat. Nos. 6,241,135 and D444,295 describe similar waist-mounted bottle/flask systems. One problem with this type of system is that the bottles are rigid, and the center of mass of the attached water bottles is relatively far from the center of mass of the runner. Furthermore, as the bottles are drained with use, water is free to slosh about. Consequently, it is difficult to provide motion control for these bottles, and the bouncing of the rigid bottles against the user is uncomfortable.
Personal hydration systems used by cyclists employ a flexible bladder encased in a fabric pack and mounted upon the cyclist""s back with shoulder straps. Fluid is delivered by a tube with a bite-valve that delivers fluid when the user bites down on the end; one embodiment of this type of hydration system is disclosed in U.S. Pat. No. 5,060,833. Because of the bent-over posture of a cyclist, the elevated position of the pack relative to the user""s mouth creates a hydrostatic head that allows for gravity-driven flow of fluid from the pack to the user""s mouth. Although this type of hydration system has seen widespread use among cyclists, runners have not embraced this type of system for two important reasons: lack of motion control and difficulty in drawing water from back level to the mouth level due to the upright posture of the runner. Although such a device, when mounted on the back, is suitable for a cyclist whose body remains relatively stable in both the horizontal and vertical planes, the lack of motion control makes it unsuitable for a runner, whose torso tends to oscillate, creating unacceptably large oscillations of the pack in the vertical (bounce) and horizontal (sway) directions. This motion of the pack can chafe the user, and fatigue the upper back, neck, and shoulder muscles. There is little that can be done to increase the amount of motion control of a back-mounted pack, as increased strap tension produces unacceptable stress on the user""s neck, back, and shoulder muscles. Furthermore, because of the upright posture of the runner, the pack is located below the user""s mouth, and the loss of a hydrostatic head results in a need to draw water by suction, a difficult task when running.
Manufacturers of back-mounted hydration packs have attempted to adapt these devices for runners so that they may be worn about the waist or hips. These waist-mounted packs are essentially back-mounted designs retro-fitted with a waistband, designed without consideration of the unique needs of runners. Because of the lower center of gravity relative to back-mounted packs, placement of a hydration pack at waist level is desirable. However, this placement makes it difficult to draw the fluid to mouth level, as it requires an unacceptably high amount of suction from the user to draw the liquid from waist level to mouth level. One possible solution to this problem is to include a pump to force the liquid to mouth level; U.S. Pat. Nos. 5,645,404 and 5,571,260 describe similar devices. However, the inclusion of a pump and its obligatory power supply results in disadvantages of both increased weight and cost. Another approach is to pressurize the bladder; U.S. Pat. No. 6,409,048 utilizes compression plates on opposing sides of the bladder, and compression is achieved by a number of straps which must all be cinched up in order to squeeze the two plates together. However, this design presents several problems. As fluid is drained, the straps must be continually tightened to maintain pressure, a cumbersome task. The plates must also be stiff, turning the bladder into an uncomfortable rigid body.
Because a cyclist has little body motion relative to a runner, a back-mounted pack can be attached with loose shoulder straps. Furthermore, since there is little motion of the pack relative to the user""s back, the pack can be constructed of non-elastic woven nylon or polyester fabric. However, running produces substantial running-related movement of the muscles about the waist and hip area. To achieve sufficient motion control, the waistband must be cinched tight to prevent motion of the pack. However, as the tension of the waistband increases, so too does the pressure on the user""s muscles, tendons, and other tissue. Thus, the user of such packs is faced with a dilemma: if too loose, the pack will have too much motion, and if too tight, the result is discomfort and possible injury. Since the tissue of the waist area is in motion, the pack itself must be sufficiently pliant so that it can move with the runner. Non-elastic fabric does not allow for this, and may represent a potential source of repetitive stress injury to runners who use such systems.
Another problem that arises with the use of non-elastic cloth relates to the ability of the fabric to prevent motion of the bladder within the fabric pack. The basic design of prior art packs is a bladder within a fabric bag. Because the fabric is non-elastic, the maximum tension against the bladder is achieved only when the bladder is completely filled. As fluid is drained from the bladder, the volume of the bladder decreases, but the volume of the fabric bag does not. The bladder is thus free to bounce around, producing additional motion of the entire system. Numerous systems utilize additional straps to take up the slack created by decreasing bladder volume, however, these must be continually tightened, a cumbersome task.
One means by which to achieve motion control is to make the attached object an integral part of the runner""s body such that the amplitude of motion is reduced and more in phase with the runner. A consideration of the problems faced by women runners may be informative. Breast tissue has fluid properties, and running produces considerable motion of the tissue. The solution to this problem is provided by athletic bras designed to restrain the breast by compression against the body, an effect accomplished through the means of snug-fitting elastic fabric as shown in U.S. Pat. No. 4,174,717. This compression decreases the moment of inertia of the tissue by reducing the distance of the center of mass of the tissue to the center of mass of the subject. The elastic fabric also dampens tissue motion. The physical properties of a flexible fluid-filled bladder suggest that a similar design would work in a waist-mounted hydration system.
Delivery of fluid from waist-level to the mouth presents additional obstacles. It is not possible to use a tube delivery device while running, as this requires prohibitively large suction forces that are impossible to generate while breathing at a high rate. However, unlike cyclists, runners are free to use their hands, and it is common practice during races to provide water in disposable cups. Cups are problematic, though, as it is easy both to spill their contents and to accidentally choke when running. Squeeze bottles present less risk of spillage and choking, but are rigid, bulky, and uncomfortable due to excessive motion. Smaller bottles bounce around less, but at the cost of reduced capacity. Some designs utilize multiple small squeeze bottles to increase total fluid capacity. However, these devices are bulky and uncomfortable, and it is awkward to clean and fill multiple bottles. Furthermore, infiltration of air to displace dispensed fluid produces sloshing regardless of the size of the bottle.
Prior art hydration systems suffer from a number of additional problems. Because of the flexible nature of the bladder, fluid pools in the bottom of the bladder. This produces an uneven distribution of the fluid within the bladder, producing sloshing as a result of the increased moment of inertia of the fluid. U.S. Pat. No. 5,427,290 discloses a back-mounted system that attempts to remedy this with a baffle in the lower portion of a flexible bladder. The resultant bladder is difficult to clean and dry, however, as a large portion of the inner and outer face of the bladder remains in permanent apposition. This presents a potential health hazard, as residual fluid in the bladder can support the growth of mold and other harmful microorganisms.
Given that hydration systems are most useful in hot weather, thermal insulation is essential to prevent fluid warming. However, all prior art packs employ a design in which additional thermal insulation is sewn into the fabric pack, and this increases the complexity and cost of construction. Ideally, the fabric would not only have the desired mechanical properties, but would also provide thermal insulation without the need for additional fabric layers.
It can be seen that prior-art hydration systems for runners suffer from a number of problems, including:
a) insufficient motion control resulting from inefficient immobilization and attachment of the bladder and pack;
b) insufficient motion control resulting from air infiltration into bottles, resulting in sloshing;
c) discomfort due to inelastic fabric;
d) inability to deliver fluid to the user""s mouth in an efficient manner;
e) inefficient incorporation of thermal insulation.
Accordingly, several objects and advantages of the present invention include:
a) to provide a means for attaching a flexible fluid-filled bladder to the waist such that motion of the bladder is dampened and minimized by compression against the runner""s body;
b) to prevent pooling of liquid in the lower portion of the bladder while maintaining ease of cleaning and air drying of the bladder;
c) to provide a means for attaching the flexible fluid-filled bladder to the waist such that the pack is comfortable and does not irritate sensitive underlying tissue;
d) to provide efficient incorporation of thermal insulation to the hydration system;
e) to provide a means for delivery of fluid from the fluid-filled bladder to the mouth of the user via a small squeeze bottle that is securely attached to the waist, fits easily in the hand, and can be removed from the waist and raised to the mouth of the user for dispensing;
f) to provide a means for automatic filling of the squeeze bottle from the flexible bladder attached to the waist;
g) to provide a means for the prevention of air infiltration into the system to prevent sloshing.
Other objects and advantages will become apparent from a consideration of the following description and drawings.
The following invention is a personal hydration system designed for runners and joggers, and consists of a flexible bladder that contains potable fluid. The bladder is enclosed in a flexible, elastic fabric pack and fastened about the waist of the user. The flexible fluid-filled bladder is constrained by compression against the user""s body by the tensioned outer fabric layer of the pack. Because tension in the elastic outer fabric layer is maintained automatically as the bladder volume decreases with fluid consumption, compression of the bladder against the user""s body is maintained at all times, providing constant motion control. A semi-rigid plastic compression plate fits between the bladder and the outer fabric layer of the pack, providing uniform distribution of force against the bladder. Snaps pinch the lower portion of the bladder together at a point, and prevent fluid from pooling in the lower half of the flexible bladder. Fluid is delivered to the mouth of the user by means of a small squeeze bottle mounted on the waist and connected to the main reservoir by a tube that provides automatic filling of the squeeze bottle. One-way check valves bias fluid flow from the main bladder to the squeeze bottle and to the user""s mouth, thus preventing air infiltration into either the satellite bottle or main bladder, a feature that eliminates sloshing. The bottle is easily removed to deliver fluid to the mouth of the user, and is easily attached to the waist when not in use. Because the squeeze bottle has a small mass and is attached firmly to the user""s waist when not in use, it does not produce any appreciable motion when running.